Change of clinical characteristics of ulcerative colitis in Japan: Analysis of 844 hospital-based patients from 1981 to 2000

BACKGROUND: Although the number of ulcerative colitis patients has increased rapidly in Japan, few reports have been published regarding their clinical aspects. We investigated the clinical characteristics and chronological change of ulcerative colitis in Japanese patients. METHODS: Patients diagnosed with ulcerative colitis during the period from 1981 to 2000 were registered and their clinical profiles were analyzed. The chronological changes in clinical aspects, such as onset age, sex distribution, severity, extent of disease, clinical course, and corticosteroid use, were also determined. RESULTS: A total of 844 patients were registered, composed of 431 men and 413 women, with a median onset age of 34 years. The proportion of mild colitis and proctitis was significantly larger in patients with an onset at over 60 years of age, relative to those with an onset at less than 30 years (P<0.016). The proportion of ulcerative colitis patients with old age onset (P=0.09), male sex (P<0.01), mild colitis (P<0.01), proctitis (P<0.01), one-attack-only type (P<0.01), and not-treated-with-corticosteroid (P<0.01) demonstrated a chronological increase from 1981 to 2000. CONCLUSIONS: The distinctive clinical features and chronological change were seen in Japanese ulcerative colitis patients in recent years. Our data can help understand clinical aspects of ulcerative colitis patients in Asia, where the incidence of ulcerative colitis is still increasing.